Thermostatic control of gas range burners



May 8, 1962 J. T. DONER ET AL THERMOSTATIC CONTROL OF GAS RANGE BURNERS 2 Sheets-Sheet 1 Filed April 28, 1958 POI ZmI;

INVENTORS:

.EFwOSKMIP May 8, 1962 J. T. DONER ET AL THERMOSTATIC CONTROL OF GAS RANGE BURNERS Filed April 28, 1958 2 Sheets-Sheet 2 & m mN NO ED V. mT N H 0 J JAMES W. LANNERT %M5%@ QW 34 BY My United States Patent O 3,033,463 THERMUSTATKC *CONTRQL OF GAS RANGE BURNER?) John T. Doner, Benton Harbor, and James W. Lannert, St. Joseph, Mich, assignors to Whirlpool Corporation,

a corporation of Delaware Filed Apr. 28, 1953, Ser. No. 731,417

' 1 Ciaim. (Cl. 236-1) This invention relates to gas ranges.

The presently conventional range utilizes secondary air to support combustion at the burners, control of the heat produced being eifected by modulating the gas fiow to the burner by suitable controls such as thermostatic controls. We have found, however, that the improved efficiency of operation of power burners utilizing only pressurized primary air makes it highly desirable to utilize power burn ers in such range applications in lieu of the relatively inefficient secondary air type burners. However, the deliv cry of the gas-primary air mixture to the power burner presents a relatively complex problem. It is necessaryto control the gas flow. It is also preferable to control the air flow and maintain the proper ratio of air-to-gas in each of different predetermined combustion conditions. The present invention provides these controls.

The principal feature of this invention is to provide a new and improved gas heating means.

Another feature is the provision of such a heating means having new and improved means for-controlling operation of a power burner.

' A further feature is the provision of such a heating means including a new and improvedmixing valve for controlling the operation of the power burner.

Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a schematic representation of an arrangement in a gas range of heating means including control apparatus embodying the invention;

FIG. 2 is a plan view of a mixing valve thereof, shown in a Low Heat arrangement in full lines and a High Heat arrangement in broken lines;

FIG. 3 is a vertical section taken approximately along the line 3-3 of FIG. 2, showing the valve shutter means in the High Heat position;

FIG. 4 is a fragmentary section taken approximately along the line 44 ofFIG. 3, but showing the valve shutter means in an Off position; and

.FIG. 5 is a fragmentary section generally similar to that of FIG. 4, the valve shutter means being shown in a Low Heat position.

In the exemplary embodiment of the invention, as disclosed in the drawing, the heating elements of a range comprise a broiler power burner 11, an oven power burnair manifold 16. To control the delivery of the gas-air mixture to the burners and to assure accurate maintenance of the proper gas-to-air ratio in the mixture, similar automatic mixing valves 17, 18 and 19 are associated with'broiler burner 11, oven burner 12, and thermostat ic'ally controlled surface burner 14, respectively. A manually operable mixing valve 20 is associated with surface burner 13. Each of the burners includes low heat 1 means and high heat means, the associated'valve func-' tioning to preclude the delivery of the air-gas mixture to the burner in an 01f condition, provide a limited delivery of air-gas mixture to the low heat means, in a Low Heat condition, and provide a large delivery of air-gas mixture to the high heat means concurrently with a de- 3,33,43 Patented May 8., 1 962 "ice livery of airgas mixture to the low heat means in a High Heat condition.

As indicated above, the combustible gas and air are delivered to the mixing valves from gas manifold 15 and air manifold 16. Combustible gas is supplied to the gas manifold from a gas supply (not shown) connected by means of a conventional fitting 21 to a duct 21a leading through a suitable pressure regulator 22 and a normally closed solenoid valve 23. Air is delivered under pressure to manifold 16 from a blower 24 driven by a motor 25. Motor 25 is connected directly to one power supply line L1 and to the opposite power supply line L2 through a lead 26 and a disconnect switch 27. .To assure that a proper air supply is available for mixture with the combustible gas in the mixing valves, operation of gas solenoid valve 23 is controlled by a pressure switch 28 which, when a proper predetermined air pressure exists within manifold 16, closes a circuit from. line L1 through a lead 29 to one side of the solenoid 23a of solenoid valve 23. The other side of the solenoid 23a is connected directly to line L2 to complete the circuit.

Gas is delivered from manifold 15 to each of the mixing valves through an inlet duct 3-0 and air is delivered from manifold 16 to each of the inlet valves by an inlet duct 31. It is the function of the individual mixing valves to mix the combustible gas and air in the proper proportion to effect theoretically perfect combustion in the associated burner. From the mixing valve, the air-gas mixture is delivered to the associated burner through suitable duct means such as low heat duct 32 and high heat duct 33 associatedwith burner 11. Each of the burners comprises a burner plate formed of a porous material, such as disclosed in the Bone et a1. Patent No. 1,223,308 issued April 17, 1917.

Mixing valves 17, 18 and 19 are identical in construction, thus a detailed description of one such valve, namely valve 17, will suifice for all. Referring now more specifically to FIGS. 2 throough 5, mixing valve 17 comprises a valve body 34 defining a mixing chamber 35, an air inlet chamber 36, a gas inlet chamber 37, a first, low heat outlet 38 and a second, high heat outlet 39. An orifice plate 40 extends transversely across the inner ends of inlets 36 and 37,-and outlet 39 and is sealed to valve body 34 by a suitable gasket 34b. A shutter plate 41 is associated with the orifice plate 40 to control the flow of gas and air through the orific'e plate into chamber 35 and the flow of the mixed gasand air from the chamber through the orifice plate to the high heat duct 33. Shutter plate 41 is fixed to arshaft 42 extending outwardly through a seal 34a in body 34, and urged by a spring 43v into sliding facial engagement with orifice plate 40. Spring 43 is secured to the shutter plate and to body 34 in such manner as to bias the shutter plate and, thus, shaft 42 in a clockwise direction, as seen in FIG. 2. To facilitate the sliding action between the shutter andorifice plates, and to assure a proper seal therebetween, the shutter plate is provided with a gasket 44formed of a low friction resilient sealing material such as nylon. ,Avalve structure broadly similar to the instant valve structure is that disclosed and claimed in the co-pending applicationof I. K. Lamp Jr. and C. R. Van Der Aue, Serial No.'

721,809, filed March 17, 1958, and assigned to the assignee .ofthe instant application. 7

The portion. of inlet 36 directly under orifice plate 40 comprises'an upwardly opening arcuate recess 45. Thev portion of orifice plate 40 overlying recess 45 is provided.

with a plurality of openings, namely a small low heat opening 46, and a plurality of larger high heat-openings The gas orifices comprise a small, low'heat orifice .48

radially aligned with low heat orifice 46 relative to the axis of shaft 42, and a larger, high heat orifice 49 radially aligned with one of the air high heat orifices 47. The

inner end of high heat outlet 39 comprises an upwardly opening arcuate recess 50, and orifice plate 40 is provided with a pair of spaced openings 51 overlying recess 59 adjacent the ends thereof.

' Shutter plate 41 (including gasket 44 thereof) comprises a plurality of circumferentially spaced, radially extending shutters 52, 53, 54 and 55. In the Off position of the valve, as seen in FIG. 4, shutter 52 overlies one pair of high heat air orifices 47, and shutter 53 overlies gas orifices 48 and 49, low heat air orifice 46 and the remaining pair of high heat air orifices 47. At the same time, shuttcrs 54 and 55 are slightly displaced from an overlying relationship with outlet openings 51, wherein mixing chamber 35 is slightly vented through the main outlet duct 33.

To arrange valve 17 for a Low Heat operation, the shutter plate 41 is rotated slightly counterclockwise to the Low Heat position of FIG. 5. In this position, shutter 52 remains in overlying relationship to the clockwise pair of high heat air orifices 47, and shutter 53 remains in overlying relationship to the other pair of high heat air orifices 47, and the high heat gas orifice 49. When positioned as in FIG. 5, shutters 54 and 55 overlie outlet openings 51 thereby precluding flow to the main outlet duct 33. However, in this position shutter 53 is no longer in overlying relationship to low heat air orifice 46 and low heat gas orifice 48 and thus a small volume of combustible gas and air is permitted to enter mixing chamber 35 wherein the 'gas and air are mixed and delivered through low heat outlet 38 and low heatduct 32 to the associated burner.

To effect a High Heat operation of the power burner, shutter plate 41 is rotated in a counterclockwise direction beyond'the position of PEG. until the shutters 52, 53, 54 and 55 are disposed intermediate the orifices and openings in orifice plate 40, thereby opening all of the orifices and openings in the orifice plate. Then air enters chamber 35 through all of the air orifices 46 and 47 and gas enters the chamber through both gas orifices 48 and 49. The mixed gas and air pass from the mixing chamber 35 through both the low heat outlet 38 and the high heat outlet 39.

Means for automatically positioning the shutter plate 411 in each of the Off, Low Heat, and High Heat positions comprise a pair of solenoids 56 and 57 and spring 43. The solenoids are arranged to operate a link 59' fixed to the outer end of shaft 42 amino fixed to a mounting plate 61. secured to the top of valve body 34 by screws 62. The plunger portion 63 of low heat solenoid 56 is provided with an arm 64 having a. depending pin 65 engaging a finger 66 at one end of link .59

When the valve is in the Off and Low Heat positions. High heat solenoid 57 is mounted on plate 61 opposite low heat solenoid 56 (relative to shaft 42) and is provided with a plunger 67 having. an arm 68 pivotally connected to the end of link 59 opposite the end defined by finger portion 66.

When neither ofsolenoids 56 or 57 is energized, spring 43 urges link 59 in a clockwise direction, as viewed in FIG. 2', toabut a stop 69 upstanding from plate 61 and position shutter plate 41 as seen in FIG. 4, thereby placing the valve inv the Off condition. When solenoid 56 is energized, plunger 63 is drawn to the right, as seen in FIG. 2, and pin 65 on arm 64 forces finger 66 in a counterclockwise direction to the position shown in broken lines in FIG. 2, thereby positioning shutter plate 41 in the Low Heat position of FIG. 5. When solenoid 57 is energized, plunger 67 thereof moves to the left, as seen in FIG. 2, pulling arm 68 to the left to swing link 59 to its extreme counterclockwise movement, as seen in full lines in FIG. 2, whereby shutter plate 41 is moved to the position wherein the shutters are disfunctioning similar to pilot 70 and relay 72 associated posed intermediate the orifices and openings of the orifice plate 40, thereby placing the valve in the High Heat condition. De-energization of solenoid 57 permits spring 43 to return link 59 to the low heat position, as shown in broken lines in FIG. 2, and subsequent deenergization of solenoid 56 permits spring 43- to return the link to the OE position wherein it abuts stop 69.

Referring now to FIG. 1, the operation of broiler burner 11 and associated mixing valve 17 will be described. To ignite the combustible gas in burner 11, a pilot 70 is associated therewith. Gas is delivered to pilot 70 from a distribution duct 71 connected to duct 21a on the inlet side of valve 23, a safety relay 72, and a delivery tube 73. A thermocouple device 72a is connected to safety relay '72 and operates the safety relay to close a valve 72b thereof connecting distribution duct 71 with tube 73, preventing further delivery of gas to the pilot should the flame thereof be extinguished. Safety relay 72 further includes a normally closed switch 72c connected in series with line L2 and alead 74 connected to the moving contact 75a of a single pole, three position rotary switch '75. Movable contact 75a is selectably closable with a first fixed contact 75b connected to one side of solenoid 56 by a lead 76, and a second fixed contact 75c connected to one side of solenoid 57 by a lead 77. The other side of each solenoid is connected electrically to line L1 to complete the circuit When switch: 75 is manually adjusted to the position wherein contact 7511 is in an 01f position, as seen in FIG. 1, neither of solenoids 56 or 57 is energized and the mixing valve is arranged'in the Off condition, as shown in FIG. 4. To effect a Low Heat operation of the broiler burner 11, such as for barbecuing, switch 75 is adjusted to close moving contact 75a with first fixed contact 7512, thereby establishing a circuit through solenoid 56, and arranging the mixing valve in the condition of FIG. 5. Thus, gas and air are delivered to the mixing chamber 35 thereof through openings 48 and 46, respectively, and the resultant mixture is delivered from the mixing chamber to broiler burner 11 through joined ducts 32 and 33. To effect a High Heat opcration of broiler burner 11, such as for broiling, switch 75 is manually adjusted to close movable contact 75a with fixed contact 75c, energizing solenoid 57 and rotating the shutter plate 41 to the position where all of the orifices and openings in orifice plate 40 are uncovered, thereby delivering a predetermined large volume of gas and air mixture through ducts 32 and 33 to the broiler burner.

The operation of oven burner 12 and associated mixing valve 18 is modified somewhat from the operation of broiler burner 11, by the inclusion of a thermostat switch 78 in the associated control circuits. Switch 78 is thermostatically controlled bya thermoresponsive device 78w of conventional construction connected thereto by'a connector 78b. Switch 78' effects a temperature regulation of oven 12 by a cyclical operation of high heat-solenoid 57 of the mixing valve 18 while maintaining low heat solenoid 56 thereof continuously energized. Oven burner 12 is provided with a pilot 79 and a safety relay 8% with broiler burner 11;. The normally closed switch 80a of safety relay 80 is connected in series from line L2 through a lead 81, a single pole, single throw manual switch 82, and a lead 83 to one side of low heat solenoid- 56. Switch 82 may be manually operable or automatically operable by means such as an electric timer (not shown) as desired. The other side of solenoid 56 is connected" directly to line L1. One side of high heat solenoid 57 is connected to lead 83 by a lead 84 and a thermostatically operated contact 85 of thermostat means 78. The other side of solenoid 57 isconnecte'd through a lead 86 and a'second thermostatically operated contact 87 of switch 78' to line L1. To effect the desired operation of oven 12, manual switch 82 is closed. Thermostat contacts 85 and 87' of switch 78 are operated by thermostat 78a. Contacts 85 and 87 are normally closed and, thus",

At s

high heat solenoid 57 is energized to effect a High Heat delivery of gas-air mixture concurrently through a high heat duct 88, to a main burner portion 12a of burner 12', and a low heat duct 89, to a low heat portion 12b of burner 12. When the temperature of the oven reaches a predetermined upper value as set by thermostat means 78, contacts 85 and 87 thereof open, thereby deenergizing solenoid 57. However, as switch 82 is closed, solenoid 56 remains energized continuing a Low Heat delivery of gas-air mixture through duct 89 to low heat portion 12b of burner 12. Illustratively, valve 18 may deliver sufficient gas-air mixture in the Low Heat operation to provide approximately 1,500 B.t.u. per hour in the oven, and maintain the oven temperature at a minimum of 200 degrees Fahrenheit. Thus, the maintenance of the desired temperature in the oven is eflected by a cyclical on-and-oif operation of the high heat function under the control of the thermostat means 78 which operates, after the initial elevation of the temperature to the predetermined upper temperature, to cycle the high heat solenoid 57' rather than by modulating the gas-air delivery to the oven burner, a lower predetermined temperature of the oven during which said cycling may take place being the temperature provided by the Low Heat operation.

The operation of surface burner 14 and associated mixing valve 19 is generally similar to that of oven burner 12 and associated mixing valve 18, except that no safety relay is associated therewith, contact 90 of the thermostat switch 91 being connected directly to line L1. Thus, one side of solenoid 57 is connected through a lead 90a and the first thermostatically controlled contact of switch 91 to line L1, and the other side of solenoid 57is connected by a lead '92, through the second thermostatically controlled contact 93, a lead 94, and a single pole, single throw switch 95 to line L2. One side of solenoid 56 is connected to lead 94 and the other side of the solenoid is connected directly to line L1. Surface burner 14 is provided with a pilot 96 and the gas-air mixture is delivered to a main burner portion 14a of the burner by a high heat duct 97 and to a low heat portion 14b thereof by a low heat duct 98. The burner may be provided with a thermal sensing element 99 associated with thermostat switch 91 by a connection 100 to effect opening of contacts 90 and '93 of the thermostat whenever an upper predetermined temperature is reached at the burner. Thus, a desired temperature is maintained with surface burner 14 by an on-and-ofi cyclical operation of thermostat switch 91 to effect a cyclical operation of high heat solenoid 57, solenoid 56 remaining energized to provide a maintained low heat operation continuously during use of the surface burner 14. Illustratively, during a Low Heat operation, burner 14 may provide approximately 600 B.t.u. per hour, While in the High Heat operation the burner may provide approximately 1,000 B.t.u. per hour. As in the oven operation, the maintenance of the desired temperature by surface burner 14 is obtained by discontinuous, or on-and-oflf operation of the high heat means rather than by modulating the gas-air delivery.

As no modulation of the gas-air delivery is required, the control means for effecting automatic operation of the power burners is simple and economical, and employs conventional, readily available control parts. The novel mixing valves combine in one unit the control means for both the air and gas and assure a proper ratio thereof in the mixture delivered to the burners. To illustrate the invention, we have shown a range structure provided with a broiler, an oven, an automatic surface burner, and a manually controlled surface burner. It should be understood, however, that these or similar units may be utilized individually or in different combinations within the scope of the invention.

While we have shown and described certain embodiments of our invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as defined in the appended claim.

We claim:

in a range, heating means comprising: a power burner; means defining a mixing chamber having a first inlet for delivering air under pressure to said chamber, a second inlet for delivering combustible gas under pressure to said chamber, a first outlet for delivering a mixture of and combustible gas under pressure from said chamber at a fixed preselected high rate, a second outlet for deiivering a mixture of air and combustible gas under pressure from said chamber at a fixed preselected low rate; means for conducting the mixtures of air and combustible gas from said outlets to said power burner; means providing a plurality of orifices across each of said inlets; a control member arranged in one position to close said second outlet and all of said iniet orifices, in a second position to close said second outlet and less than all of said inlet orifices, and in a third position to open said second outlet and all of said inlet orifices; and means for operating said control member to permit delivery of air and gas mixture through said second outlet continuously, nermit delivery of air and gas mixture through said first outlet continuously until the temperature produced by the burner rises to a preselected upper temperature, and subsequently discontinue the delivery of air and gas mixture through said first outlet when the temperature produced by the burner drops to a lower preselected temperature, the temperature produced by the burner being subsequently maintained between said upper and lower preselected temperatures by the continuous delivery of air and gas mixture from the second outlet and the cyclical delivery of air and gas mixture from the first outlet.

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